[A11y] Add label for ProfileListActivity

[rt4914]

Task

Introduce label for ProfileListActivity as Profile List.

Reference PR: #2750

When you create a PR for this, make sure you add test to check the functionality. Also, suggest working on this PR only if its your first or second PR to Oppia-Android project.

General Explanation

When Talkback is on, whenever we click on any option which leads to new screen the reader will automatically read the label associated with that screen first. If in case label in not present then it will read app name i.e. Oppia.

Example

device-2021-02-24-021647.mp4

In this above video as soon as we double-tap Battery, new screen is opened.
The reader first outputs Battery followed by Navigate up, Button and finally Battery again. In this the first Battery output is the label of this new screen which indicates the learner which screen is opened. The second Battery is because we selected the title in the screen and it's just reading that text.
So we need labels for various screens general which matches the title but if the title is dynamic then we need static label.

[AnubhavPabby]

@rt4914 Hey can you assign this issue to me

[arjunrkaushik]

@rt4914 I would like to work on this issue, as suggested to me by Abhay Garg

[prayutsu]

@arjunrkaushik As @AnubhavPabby claimed it first, we should assign this issue to him, but I am assigning you #2819 which is almost similar to this. Can you please add a comment there so can I assign that issue to you?

[Karanjot-singh]

Can I work on this issue? @prayutsu I might need some help in testing as I am fairly new to contributing.

[rt4914]

Can I work on this issue? @prayutsu I might need some help in testing as I am fairly new to contributing.

@Karanjot-singh This issue is already assigned to @AnubhavPabby

[pravesh00]

@rt4914 is this issue resolved? Can I work on this?

[rt4914]

@rt4914 is this issue resolved? Can I work on this?

@pravesh00 Thanks for your interest. Please checkout our wiki first. This will help you in setting up the project and once you sign the CLA and fill the survey form we can assign you issues to work on.